Release Notes

12
Release Notes for the Catalyst 2960-C and 2960-Plus Switches, Cisco IOS Release 15.2(3)E and Later
OL-32525-01
Limitations and Restrictions
• IGMP filtering is applied to packets that are forwarded through hardware. It is not applied to packets
that are forwarded through software. Hence, with multicast routing enabled, the first few packets are
sent from a port even when IGMP filtering is set to deny those groups on that port.
There is no workaround. (CSCdy82818)
• If an IGMP report packet has two multicast group records, the switch removes or adds interfaces
depending on the order of the records in the packet:
– If the ALLOW_NEW_SOURCE record is before the BLOCK_OLD_SOURCE record, the
switch removes the port from the group.
– If the BLOCK_OLD_SOURCE record is before the ALLOW_NEW_SOURCE record, the
switch adds the port to the group.
There is no workaround. (CSCec20128)
• When IGMP snooping is disabled and you enter the switchport block multicast interface
configuration command, IP multicast traffic is not blocked.
The switchport block multicast interface configuration command is only applicable to non-IP
multicast traffic.
There is no workaround. (CSCee16865)
• Incomplete multicast traffic can be seen under either of these conditions:
– You disable IP multicast routing or re-enable it globally on an interface.
– A switch mroute table temporarily runs out of resources and recovers later.
The workaround is to enter the clear ip mroute privileged EXEC command on the interface.
(CSCef42436)
After you configure a switch to join a multicast group by entering the ip igmp join-group
group-address interface configuration command, the switch does not receive join packets from the
client, and the switch port connected to the client is removed from the IGMP snooping forwarding
table.
Use one of these workarounds:
– Cancel membership in the multicast group by using the no ip igmp join-group group-address
interface configuration command on an SVI.
– Disable IGMP snooping on the VLAN interface by using the no ip igmp snooping vlan vlan-id
global configuration command. (CSCeh90425)
Power
• Entering the shutdown and the no shutdown interface configuration commands on the internal link
can disrupt the PoE operation. If a new IP phone is added while the internal link is in shutdown state,
the IP phone does not get inline power if the internal link is brought up within 5 minutes.
The workaround is to enter the shutdown and the no shutdown interface configuration commands
on the Fast Ethernet interface of a new IP phone that is attached to the service module port after the
internal link is brought up. (CSCeh45465)
QoS
• Some switch queues are disabled if the buffer size or threshold level is set too low with the mls qos
queue-set output global configuration command. The ratio of buffer size to threshold level should
be greater than 10 to avoid disabling the queue.